There is a case where a production device which processes or assembles a product, a component, or the like cannot meet a desired standard when originally achieved processing accuracy, heating performance, and the like change due to a change over time caused by operation of the production device. Examples of the change over time caused by operation include wear, damage, deterioration, and trouble of a component, and looseness of a fastening section. In a case where the production device cannot meet the desired standard, there occurs a problem such as an increase in percent defective, an increase in frequency of a shutdown, or an increase in amount of electric power consumption. In view of this, in order to respond to such a problem, (1) components are replaced at a timing at which an operating time or the number of times of use exceeds a set value, or (2) maintenance for inspection and repair is carried out at regular intervals by stopping the operation.
However, according to a method in which components are replaced in accordance with an operating time or the number of times of use, a state of wear or deterioration of a component varies depending on a state of use of a device. This may cause a case where a component which is sufficiently usable is wastefully disposed of, or, conversely, a case where deterioration of a component progresses than expected, so that a product percent defective increases, or a device suddenly stops. Meanwhile, according to a method in which maintenance is carried out at regular intervals, a device is stopped during the maintenance, so that production efficiency decreases.
Under the circumstances, there has been known a technique for measuring a physical quantity that changes by operation of a device, detecting presence or absence of an abnormality by comparison of the physical quantity and a preset threshold, and reporting an abnormality to a worker at a timing at which the abnormality is detected. Examples of a known method include: a method using, as a physical quantity, a result of sensing a vibration, an electric current, a temperature, or the like of a device (see Patent Literature 1), a method using a torque of a drive motor (see Patent Literature 2), a method using a pressure (see Patent Literature 3), and a method using electric power (Patent Literature 4).